[Histonet] hematoxylin

[Hana Peter]

Hello!
I have two liters of hematoxylin Lillie Mayer modification, "home made" a
month ago. One bottle (1L) seems perfectly OK, but the other have some
precipitate (actually two or three very large crystals). They were stored in
the same cupboard at room temperature. Two weeks ago we were a few days
without the heating.
Does anyone have an idea what might have happened to my hematoxylin? Can I
do something to save this liter or should I discard it? What can I do to
prevent it from forming crystals in the future?
Thank you very much in advance!
Hana Peter